John McCain takes jab at Donald Trump's war deferments

Senator John McCain has launched a thinly-veiled attack on President Donald Trump in an interview where he criticised wealthy young men who avoided war "with a doctor's note for a bone spur" the same reason the President gave for avoiding war.

In an interview with C-SPAN on Sunday night (local time), 81-year-old McCain spoke about the Vietnam War.

"One aspect of the conflict, by the way, that I will never, ever countenance is that we drafted the lowest-income level of America, and the highest-income level found a doctor that would say they had a bone spur," McCain said in the interview.

"That is wrong. That is wrong. If we are going to ask every American to serve, every American should serve."

Trump - who has historical feud with McCain - received five military draft deferments during the Vietnam War, including one medical deferment after he was diagnosed with bone spurs in his foot. The others were because he was a college student at New York Military Academy.

In 2015, Trump criticised McCain for spending five years as a prisoner of war during the Vietnam War - during which he was tortured - saying McCain was "not a war hero".

"I like people that weren't captured," the then presidential hopeful said.